Fine electronic components, such as integrated circuit chips or devices, terminal pads of printed circuit boards, liquid crystal displays, etc., have electrical connecting parts for connection to external circuits. In the case of connection of chips to external circuits, in particular, these electrical connecting parts are present at very high density, and separation of each of these electrical connecting parts from adjoining parts is typically 0.1 mm or less. These electrical connecting parts existing at high density have to be electrically insulated from adjoining parts in order to avoid occurrence of short circuit between them. Therefore, an anisotropic electrically conductive structure which is electrically conductive only in one direction, and is electrically insulating in other directions, has been generally used for these connecting parts.
Various documents are known on an anisotropic electrically conductive structure. For example, Patent Document 1 (Japanese Unexamined Patent Publication (Kokai) No. 9-330774) discloses a stacking connecting connector interposed between two stacked objects to be connected which connects these objects to each other when the two objects to be connected are pressed in prescribed direction so as to approach to each other, comprising contacts for connecting the two objects to be connected, and an insulator for holding these contacts. The connector is pressed and fixed to the two objects to be connected using mechanical means such as bolts and nuts so as to complete the connection. Such mechanical means, however, are bulky, and therefore may become an impediment to downsizing and miniaturization of electronic parts.
On the other hand, Patent Document 2 (Japanese Unexamined Patent Publication (Kokai) No. 62-117207) discloses an isotropic electrically conductive polymer material in which a multiplicity of electrically conductive members penetrate through a polymer layer and are arranged with uniform separation so as to be electrically insulated from each other, wherein each of said members has an electrical conductive material extending across the thickness of the polymer layer so as to conduct electric current across the polymer layer through said members.
Also, Patent Document 3 (National Publication (Kohyo) No. 2000-511339) discloses an anisotropic electrically conductive structure comprising a dielectric matrix material having a first surface and a second surface, at least one passage extending from said first surface of said material to said second surface of said material, and an electrically conductive member in said passage, wherein said electrically conductive member includes at least one electrically conductive element having maximum dimensions of at least 5% of the length of said passage and at least 10% of the width of said passage.
In Patent Documents 2 and 3, it is disclosed that thermoplastic resins, thermoplastic elastomers, and heat curable materials can be used as the polymer material or the dielectric material, and that, when adhesion to connecting parts is required, hot pressure sensitive adhesive hot-melt can also be used. However, since these materials soften at the time of connection and may be fluidized so that it is not always easy to maintain insulation between conductive passages.